The surface air temperature at Watson Lake in the southern Yukon Territory of Canada (station identifier CYQH) fell to -56Âº F (-49Âº C) at 16 UTC on 14 January 2011. About 2 hours later, a comparison of AWIPS images of 4-km resolution GOES-11 10.7 Âµm IR and 1-km resolution POES AVHRR IR data (above) showed the signature of cold air that had settled into the valleys across that region — this signature was naturally much clearer on the higher resolution POES AVHRR image. The coldest surface IR brightness temperature on the POES AVHRR IR image was -52Âº C (-62Âº F) just to the southeast of Watson Lake. Also note the northeastward “parallax shift” of the warmer cloud features on the GOES-11 image, due to the high viewing angle from that geostationary satellite (which was situated over the Equator at 135Âº West longitude).